The habitually punctual make all their mistakes right on time. - Laurence J. Peter

Against logic there is no armor like ignorance.

It is true that work can expand to fill the time allotted but it can expand far beyond that. It can expand beyond the life of the organization and the company can go bankrupt, a government can fall, a civilization can crumble into barbarism, while the incompetents work on.

In time, every post tends to be occupied by an employee who is incompetent to carry out its duties. Do not be fooled by apparent exceptions.